My wireless network has been based on a WLC2504 controller with two 2602 AP’s. The network has been running quite well, with of course the caveats that came with the different WLC releases. With the maturity of Mobility Express (ME), the need for a dedicated controller for such as small sized wireless network has basically become obsolete as one of the AP’s becomes the master controller in the network. I was able to acquire 2 1852 AP’s with ME, time to upgrade my wireless network to 802.11ac with ME..

Design considerations

Joep Remkes, a Cisco Systems Engineer, was kind enough to share the Cisco Mobility Express Quick Start Guide and explained to me what Mobility Express actually is. And the latter is actually key for the understanding. Because, in effect, a mini Wireless Lan Controller (mini WLC) is running as a virtual machine inside the AP code. And as it is a separate machine, it has a separate IP address and you manage it separately. And that is something you really need to keep in mind when deploying mobility express. Another thing that you need to be aware off is that FlexConnect is used for breakout, so yes, there is a CAPWAP tunnel, but not for client traffic.

The figure below displays functionally how mobility express is essentially organised.

So in a mobility expres deployment, there is a master election (e.g. which AP in your network becomes your controller and manages the configuratoin). The diagram below describes the flow that an AP goes through when booting up.

Image courtesy of Cisco Systems

Setting up a fresh ME deployment

Setting up a ME based deployment is really easy. Of course the Cisco guide is more extensively written, but for my deployment, I executed the following steps

Create VLAN and DHCP scope

As I run an external DHCP server (my IOS switch) and within a ME setup, you cannot use both external and internal DHCP server, I created a new AP-VLAN (221) and configured the DHCP scope on my core swiitch. There are no special DHCP options required for the discovery of the master AP on your network. 

na-vur-c3560-1#config term
na-vur-c3560-1(config-vlan)#vlan 221
na-vur-c3560-1(config)#name ap-net
na-vur-c3560-1(config)#ip dhcp excluded-address
na-vur-c3560-1(config)#ip dhcp excluded-address
na-vur-c3560-1(config)#ip dhcp pool wireless-ap

Configure interface for your master AP

Once the VLAN and DHCP is configured, configure the switch with an SVI (layer 3 interface) and configure an interface where the AP will be connected on

na-vur-c3560-1(config)#interface vlan221
na-vur-c3560-1(config-if)#name ap-net
na-vur-c3560-1(config-if)#ip add
na-vur-c3560-1(config-if)#no shut
na-vur-c3560-1(config-if)#interface GigabitEthernet0/3
na-vur-c3560-1(config-if)#description ge0-0-1852-master
na-vur-c3560-1(config-if)#switchport trunk encapsulation dot1q
na-vur-c3560-1(config-if)#switchport mode trunk
na-vur-c3560-1(config-if)#switchport trunk native vlan 221

If you use vlan’s, you have to use the native vlan for that network, so that the master AP gets an IP address in the proper network. I’ve added the configuation spanning-tree portfast trunk as STP blocking can have some delay for client onboarding.

Bootup the master AP

Now plugin the master AP and wait until the AP is booting. The AP master selection proces will be executed. Wait until you see the SSID “CiscoAirProvision” The SSID “CiscoAirProvision” is used by Cisco for over the air configuration. Use password “password” to connect to the network. You will get an internal ip-adress.

Connect to SSID “CiscoAirProvission” and configure

Once you’re connected, start a browser and go to the site or easier,

Run through the steps of the wizard (see screenshots below) and apply the values that are appropriate to your environment

Apply settings and test with the Master AP

Now apply the settings, wait until the AP is rebooted and connect to your network.

Once connected, use your browser to check that you can connect to the IP address of the master AP controller. As you’ll see, the GUI is similar to the new WLC 8.2+ frontpage and is very recognisable.

Now configure other AP’s and switch interfaces

Once the Master AP works, configure other PoE enabled ports on your switch for the other AP’s, plug them in and wait. After some time, the AP’s will join the master AP and your wireless network is setup! For this, I’ve used the same interface config as the master AP, except for the description.

Upgrading of a ME deployment is slightly different than your controller based deployment, that will be another blog post (soon)

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